What is a tidal surge?

A tidal surge, also called a storm surge, is a change in sea level that is caused by a storm.

How is it caused?

Storm waves at Tynemouth Lighthouse

According to the Met Office, the main cause of this is high winds pushing the sea water towards the coast, causing it to pile up there. There is also a smaller contribution from low pressure at the centre of the storm “pulling” the water level up.

This is called the inverse barometer effect, and is similar to what happens when you drink through a straw.

The strong winds generate large waves on top of the surge which can cause the water to spill over the top of sea walls and banks, causing a flood risk.

Which places are at most risk of flooding?

Mainly beaches and promenades along the coast, as well as riversides, including the Quayside area in Newcastle. The Environment Agency and local authorities continually monitor the risk and take precautions to prevent flooding.

Are storm surges common?

They are relatively rare, with the last major one reported in December 2013. At that time, a large storm surge hit the east coast of the UK causing widespread flooding. It was a prime example of low pressure, high winds and high tidal conditions combining. The Quayside in Newcastle was badly affected at the time and became flooded.

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Have there been any major tidal surges in the UK which resulted in loss of life?

Yes, there was quite a bad one on the night of January 31, 1953.

A storm in the North Sea caused a surge which occurred at the same time as a high spring tide. Although the storm and surge were forecast in advance, public warning systems were not very effective at the time and many people were not prepared for the flooding.

More than 2,500 people were killed around the North Sea coastline, including 307 in England and 19 in Scotland.

As well as the loss of life, the flooding caused a great deal of damage to people’s homes and businesses and ruined large areas of farmland. Following the incident, the Government invested much more in improved sea defences and effective warning systems.